content: /*
   * Copyright 2017 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.reactive4javaflow.impl.operators;
  
  import hu.akarnokd.reactive4javaflow.*;
  import hu.akarnokd.reactive4javaflow.functionals.CheckedFunction;
  import hu.akarnokd.reactive4javaflow.fused.ConditionalSubscriber;
  
  import java.util.Objects;
  import java.util.concurrent.Flow;
  
  /**
   * Maps each 'rail' of the source ParallelFolyam with a mapper function.
   *
   * @param <T> the input value type
   * @param <R> the output value type
   */
  public final class ParallelMap<T, R> extends ParallelFolyam<R> {
  
      final ParallelFolyam<T> source;
  
      final CheckedFunction<? super T, ? extends R> mapper;
  
      public ParallelMap(ParallelFolyam<T> source, CheckedFunction<? super T, ? extends R> mapper) {
          this.source = source;
          this.mapper = mapper;
      }
  
      @Override
      public void subscribeActual(FolyamSubscriber<? super R>[] subscribers) {
  
          int n = subscribers.length;
          @SuppressWarnings("unchecked")
          FolyamSubscriber<? super T>[] parents = new FolyamSubscriber[n];
  
          for (int i = 0; i < n; i++) {
              FolyamSubscriber<? super R> a = subscribers[i];
              if (a instanceof ConditionalSubscriber) {
                  parents[i] = new ParallelMapConditionalSubscriber<T, R>((ConditionalSubscriber<? super R>)a, mapper);
              } else {
                  parents[i] = new ParallelMapSubscriber<T, R>(a, mapper);
              }
          }
  
          source.subscribe(parents);
      }
  
      @Override
      public int parallelism() {
          return source.parallelism();
      }
  
      static final class ParallelMapSubscriber<T, R> implements FolyamSubscriber<T>, Flow.Subscription {
  
          final Flow.Subscriber<? super R> actual;
  
          final CheckedFunction<? super T, ? extends R> mapper;
  
          Flow.Subscription s;
  
          boolean done;
  
          ParallelMapSubscriber(FolyamSubscriber<? super R> actual, CheckedFunction<? super T, ? extends R> mapper) {
              this.actual = actual;
              this.mapper = mapper;
          }
  
          @Override
          public void request(long n) {
              s.request(n);
          }
  
          @Override
          public void cancel() {
              s.cancel();
          }
  
          @Override
          public void onSubscribe(Flow.Subscription s) {
              this.s = s;
  
              actual.onSubscribe(this);
          }
  
          @Override
          public void onNext(T t) {
              if (done) {
                  return;
              }
              R v;
  
              try {
                  v = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null value");
              } catch (Throwable ex) {
                  FolyamPlugins.handleFatal(ex);
                  cancel();
                  onError(ex);
                  return;
              }
  
              actual.onNext(v);
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  FolyamPlugins.onError(t);
                  return;
              }
              done = true;
              actual.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (done) {
                  return;
              }
              done = true;
              actual.onComplete();
          }
  
      }
      static final class ParallelMapConditionalSubscriber<T, R> implements ConditionalSubscriber<T>, Flow.Subscription {
  
          final ConditionalSubscriber<? super R> actual;
  
          final CheckedFunction<? super T, ? extends R> mapper;
  
          Flow.Subscription s;
  
          boolean done;
  
          ParallelMapConditionalSubscriber(ConditionalSubscriber<? super R> actual, CheckedFunction<? super T, ? extends R> mapper) {
              this.actual = actual;
              this.mapper = mapper;
          }
  
          @Override
          public void request(long n) {
              s.request(n);
          }
  
          @Override
          public void cancel() {
              s.cancel();
          }
  
          @Override
          public void onSubscribe(Flow.Subscription s) {
              this.s = s;
  
              actual.onSubscribe(this);
          }
  
          @Override
          public void onNext(T t) {
              if (done) {
                  return;
              }
              R v;
  
              try {
                  v = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null value");
              } catch (Throwable ex) {
                  FolyamPlugins.handleFatal(ex);
                  cancel();
                  onError(ex);
                  return;
              }
  
              actual.onNext(v);
          }
  
          @Override
          public boolean tryOnNext(T t) {
              if (done) {
                  return false;
              }
              R v;
  
              try {
                  v = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null value");
              } catch (Throwable ex) {
                  FolyamPlugins.handleFatal(ex);
                  cancel();
                  onError(ex);
                  return false;
              }
  
              return actual.tryOnNext(v);
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  FolyamPlugins.onError(t);
                  return;
              }
              done = true;
              actual.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (done) {
                  return;
              }
              done = true;
              actual.onComplete();
          }
  
      }
  }
  